Rock duster



- Sept- 8? 1936- A. J. GURN EY/ 5 ROCK DUSTER Filed May 16, 1934 3Sheets-Sheet l Sept. 8, 1936. A. J. GURNEY ROCK DUSTER Filed May 16,1934 3 SheetS Sheet 3 v SN Patented Sept. 8, 1936 PATENT OFFICE ROCKDUSTER Albert J. Gurney, Canton, Ohio, assignor to The American MineDoor Company, Canton, Ohio,

a corporation of Ohio Application May 16, 1934, Serial No. 725,887

9 Claims.

The invention relates to apparatus for spraying rock dust or the likeupon the ceilings, walls and floors of coal mines, in order to cover ormix with the coal dust ordinarily deposited in such places, for thepurpose of preventing explosions of the coal dust, and more particularlyto a simple and inexpensive rock duster especially adapted for use insmaller mines.

It is common practice to spray the interiors of mine tunnels with rockdust, and apparatus, such as'shown in my prior Patent No. 1,852,649, iscommonly used for this purpose in large mines, but since it is onlynecessary to spray with rock dust about twice a year, the cost of suchlarge apparatus makes the use of the same prohibitive to the small mineoperator.

Therefore, an object of the present improvement is the provision of asmall and inexpensive rock duster which is adapted for use in small coalmines, and which has sufficient capacity to carry the rock dust to everypart of a small mine.

Another object of the improvement is to provide a new and novel form ofmixing nozzle for mixing the air blast and rock dust and discharging themixture through a hose or the like.

A further object is toprovide a novel form of gear reduction foroperating the working parts of the rock duster.

A still further object is 'to provide a hopper for containing the rockdust so shaped that the motor and blower are protected thereby fromdust.

The above objects, together with others which will be apparent from theaccompanying drawings and following description, or which maybe laterpointed out, may be attained by constructing the improved rock duster inthe manner illus trated in the accompanying drawings, in which Figure 1is a top plan view of the improved rock dusterfwith parts'broken awayfor the purpose of illustration; I

Fig. 2, a rearend elevation of the apparatus with portions broken away;v

Fig. 3,an enlarged longitudinal section through the improved "mixingnoz'zle which mixes the air blast and rock dust and discharges themixture through a hose or the like;

Fig. 4; an elevation of the improve'd'gearreduc tion;

Fig; 5, a transverse section through the gear reduction'taken as on theline 55, Fig. 14; and

Fig. 6, a section as on the line 6-6, Fig. 4.

Similar numerals refer to similar parts throughout the drawings.

The improved apparatus is designed to be moved through a mine upon"rails, and for this purpose may include the frame l0, provided withaxles l I having flanged wheels l2 arranged to run upon the rails I3.

The hopper M is mounted upon the frame, for the purpose of containing asupply of rock dust, this hopper preferably being of substantially V-shape, as best shown in Fig. 2, and having the overhanging, horizontalshelves I 5 at its upper end, terminating in the depending,strengthening flanges l6. each end of the hopperto close the endsthereof and to strengthen and support the shelves IS.

The motor I 8, which operates the working parts of the apparatus, may belocated upon the frame adjacent to one side of the- V-shape hopper l4and beneath the adjacent shelf l5 so that it is protected from rock dustspilling upon the same from the trough and the blower l 9 may be housedin the same manner upon the other side of the hopper and beneath theother shelf l5 so that both of these parts are protected by the troughand shelves thereon.

A gear housing 20 is located at the rear end of the hopper M to enclosethe drive and reduction gear from the motor to the blower and conveyerscrew 2| respectively. The shaft 22 of the motor may have a sprocketwheel 23 fixed thereon, within the gear'housing 20, a chain 24 passingover said sprocket wheel and over a similar sprocket wheel 25 fixed uponthe shaft 26 of the blower l9 whereby the blower is driven directly fromthe motor. For the purpose of driving the conveyer screw 2| at thedesired speed, a novel reduction gearing is provided which may be drivenby a pinion 2'! fixed upon the motor shaft. 22 and meshing with a gear28 keyed to the hub of an eccentric 29. The eccentric 29 is journaledupon a shaft 30 secured within the gear housing, and is surrounded bythe eccentric band 3| which may be provided with an annular groove toreceivethe split spring ring 32, the angular ends 33 of which may bereceived in a cut-out portion of the groove indicated at 34. When thissplit spring ring is sprung into place as shown in Fig. 4,.the eccentricband 3| will be retained upon the eccentric 29.

A ratchet gear 35 is fixed upon the shaft 36 of the conveyer screw 2| asby the keys 31. A rigid arm 38 is carried by the eccentric band 3| andis pivotally connected at its end, as by the stud 39, to the outerrocker arm 40 having the angular free end 4|. A journal portion-42 isformed upon the inner end of the rocker arm 40 and is journaled upon thejournal portion 43 of the inner rocker arm 44.

An end plate I! may be attached to IN) V A pawl 45 is pivoted upon thestud 39 and a spring 46 is provided for normally urging said pawl intoengagement with the teeth of the ratchet gear 35. An arm 4'! is pivotedas at 48 upon the eccentric band 3|, the other end thereof beingpivotally connected to the inner rocker arm 44 as by the stud 49 uponwhich is pivoted the pawl 50, similar to the pawl 45 and arranged to benormally urged into contact with the teeth of the ratchet gear 35 as bythe spring Each of the pawls 45 and 50 is provided with a curved lug 52adapted to ride over the arcuate surfaces 53 of the pawl release 54which is provided with a journal portion 55 journaled upon the bushing56 surrounding the reduced portion 51 of the conveyer screw shaft 36 andalso journaled within the bearing boss 53 formed upon the gear housing20. A thrust ball 59' may be provided within the recess 60 of thejournal portion 55 bearing against the reduced end 51 of the shaft 36,which shaft may be journaled through a bushing 6| provided in thebearing boss 62 formed in the housing 20.

A handle lever 63 is fixed to the journal portion 55 of the pawl releaseas by the collar 64 formed upon the handle and the pin 65 passed throughsaid collar and through the journal portion 55. This handle is adaptedto be moved across the control segment 66 fixed upon the rear side ofthe housing 20 and having apertures 61 adapted to be selectively engagedby a pin 68 upon the handle knob 69 for holding the pawl release in offposition or in position for feeding sufllcient rock dust to the feed jetto accommodate a T hundred foot hose or fifty foot hose, as indicated onFig. 2 of the drawings.

It will be seen that as the handle is rotated to the off position, thearcuate surfaces 53 of the pawl release will be so positioned thatthrough the entire stroke of the pawls 45 and 56, the curved lugs 52 ofthe pawls will ride upon the arcuate surfaces 53 of the pawl release sothat the ratchet gear 35, and with it the conveyer screw, will not berotated. Regardless of the posi tion of the pawl release 54, the blowerwill continue to operate directly from the motor during all times thatthe motor is in operation.

The conveyer screw 21 is located in a substantially half-round groove ortrough 16 in the bottom of the V-shaped hopper l4 and the forward endportion thereof maybe enclosed by the substantially half-round plate H,said forward end of the conveyer screw passing through the opening 12in'the forward end wall of the hopper and extending into the inner feedtube 13 of the mixing nozzle, the end of the shaft being reduced as at74 and journaled in the bushing 15 within the bearing member 16 whichmay be centrally supported in spaced relation within the feed tube 13 asby the ribs 11,- a semi-elliptic nose 18 being formed upon said bearingmember.

The forwardend of the inner or rock dust feed tube 13 is tapered as.shown at 19, the taper being considerably less than the taper of thenose 18 or the tapered forward end portion 80 of the outer or air feedtube 8|. This tapered forward end portion 86 of the outer feed tubeterminates beyond the tapered end 19 of the inner feed tube at adistance substantially one-half the diameter of the inner feed tube.This outer or air feed tube may be provided at its rear end with theangular flange 82 having the central opening 83 adapted to fit upon theshoulder 84 of the inner or rock dust feed tube 13. The flange 82 isalso adapted to fit against a similar flange 85 upon the inner feed tubewhich fits against the adjacent end wall of the hopper I4, the flangesbeing adapted to be connected thereto in any usual and well knownmanner.

An outwardly tapered inlet neck 86 is provided 5 upon the outer or airfeed tube 8| provided at its end with a flange 87 adapted to beconnected to a similar flange 88 upon the air pipe 89 leading from theblower IS. The discharge end of the feed tube 8|, beyond the taperedportion 80, may be flared slightly outward as at 9|, terminating in aflange 92 to which a hose coupling 93 may be attached as by bolts 94 forthe purpose of securing a hose thereto.

In the operation of the improved rock duster, the same may be moved overthe usual rails 43 in the mine by means of a locomotive or the like andthe rock dust from the hopper I4 is conveyed by the conveyer screw 2|into the inner or rock dust feed tube 13 and as it is pushed forwardinto the tapered end portion 19 thereof, the rock dust may expand in thespace between said tapered discharge end of the feed tube 13 and thetapered nose 18 and is picked up by the air blast passing through theouter or air feed tube 8 I, the mixture being carried through thetapered portion 80 of the outer feed tube and then slightly expanded asit passes through the flared portion 91 thereof and is carried to thehose, by means of which it may be sprayed upon the ceilings, walls andfloor of the mine tunnel.

Where a short hose is connected to the mixing nozzle, the air creates avacuum beyond the re stricted end 79 of the inner or rock dust feedtube, drawing the dust out into the air stream. Where a long hose isconnected to the nozzle, the resistance of the air caused by frictionforces a dust plug back into the end of the rock dust feed tube '13,preventing back pressure of air from forcing rock dust back into thehopper. Without means for forming this dust plug, most of the air wouldpass back through the feed tube 13 into the hopper.

The handle lever 63 may be operated across the control segment 66 toadjust the gear reduction, shown in Fig. 4, so as to provide the properrate of feed of rock dust for either fifty foot or one hundred foot hoseor so as to entirely out off the supply of rock dust when desired.

I claim:

1. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube, the forward end portion of the outer feed tube being taperedmore than the inner feed tube, and terminating beyond the end of theinner feed tube at a distance substantially onehalf the diameter of theinner feed tube, means for feeding rock dust and the like into the rearend of the inner feed tube, and means for connecting a hose to theforward end of the outer feed tube.

2. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom, the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube, the forward end portion of the outer feed tube being taperedmore than the inner feed tube and terminating beyond the end of theinner feed tube at a distance substantially one-half the diameter of theinner feed tube and then outwardly flared, means for feeding rock dustand the like into the rear end of the inner feed tube, and means forconnecting a hose to the forward end of the outer feed tube.

3. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom, the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube, a central obstruction of uniform diameter within the innerfeed tube having a forwardly disposed tapered nose, means for feedingrock dust and the like into the rear end of the inner feed tube, andmeans for connecting a hose to the forward end of the outer feed tube.

4. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom, the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube, a central obstruction of unifom diameter Within the innerfeed tube having a forwardly disposed nose tapered more than the innerfeed tube, means for feeding rock dust and the like into the rear end ofthe inner feed tube, and means for connecting a hose to the forward endof the outer feed tube.

5. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom, the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube, the forward end portion of the outer feed tube being taperedmore than the inner feed tube, a central obstruction of uniform diameterWithin the inner feed tube having a forwardly disposed tapered nose,means for feeding rock dust and the like into the rear end of the innerfeed tube, and means for connecting a hose to the forward end of theouter feed tube.

6. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom, the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube,

the forward end portion of the outer feed tube being tapered more thanthe inner feed tube, a central obstruction of uniform diameter withinthe inner feed tube having a forwardly disposed nose tapered more thanthe inner feed tube, means for feeding rock dust and the like into therear end of the inner feed tube, and means for connecting a hose to theforward end of the outer feed tube.

7. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom, the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube, a feed screw for feeding rock dust and the like into the rearend of the inner feed tube, a bearing for said feed screw within theinner feed tube having a forwardly tapered nose, and means forconnecting a hose to the forward end of the outer feed tube.

8. A rock duster including a mixing nozzle comprising an outer feedtube, means for admitting air to the rear portion thereof, an inner feedtube within the outer feed tube and spaced therefrom, the forward end ofthe inner feed tube being tapered and terminating short of the outerfeed tube, a feed screw for feeding rock dust and the like into the rearend of the inner feed tube, a bearing for said feed screw within theinner feed tube having a forwardly disposed nose tapered more than theinner feed tube, and means for connecting a hose to the forward end ofthe outer feed tube.

9. A rock duster including mixing nozzle comprising an outer feed tube,means for admitting air to the rear portion thereof, an inner feed tubewithin the outer feed tube and spaced therefrom, the forward end of theinner feed tube being tapered and terminating short of the outer feedtube, the forward end portion of the outer feed tube being tapered morethan the inner feed tube, a feed screw for feeding rock dust and thelike into the rear end of the inner feed tube, a bearing for said feedscrew within the inner feed tube having a forwardly tapered nose, andmeans for connecting a hose to the forward end of the outer feed tube.

ALBERT J. GURNEY.

